Phase Controlled Converter Harmonic Reduction

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Solution Overview

Problem

High-power heating processes in thin-film solar cell production using phase control result in non-sinusoidal current flows, leading to significant harmonics in AC networks, which violate regulatory standards and cause energy losses.

Innovation Solution

A method and device that switch off specific half-waves for each consumer, using a second phase control angle, allowing one consumer to use only positive half-waves and the other only negative half-waves, reducing the deviation from sinusoidal current flow and minimizing harmonics, especially at low loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phase angle control is used to reduce power consumption, then energy efficiency is improved, but current waveform distortion increases and harmonics are generated

Engineering Contradiction:
Improveenergy efficiencyVSAvoidharmonics
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent segments the AC waveform into multiple intervals within each half-wave, applying different phase control angles to different segments. This segmentation allows the system to maintain energy efficiency while distributing harmonic generation across multiple controlled segments, reducing overall waveform distortion compared to uniform phase control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic variation of phase control angles across consecutive half-waves, where the control pattern repeats periodically. This periodic action creates a structured harmonic cancellation effect where harmonics generated in one half-wave are counterbalanced by opposing harmonics in subsequent half-waves, reducing net harmonic distortion.

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If phase control angle is increased to reduce power, then energy consumption is reduced, but current deviation from sinusoidal shape increases

Engineering Contradiction:
Improvepower consumptionVSAvoidcurrent waveform shape
Core Design Contradiction:
Use of energy by moving objectVSShape

Solution Approach 1:

The patent dynamically adjusts phase control angles based on the specific interval and half-wave characteristics rather than using a fixed angle. This dynamic adaptation allows the system to optimize between power reduction and waveform quality in real-time, maintaining better sinusoidal shape while achieving energy savings.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes multiple parameters including phase control angles, interval boundaries, and half-wave assignments to optimize both power consumption and waveform quality. By varying these parameters periodically and adaptively, the system achieves energy efficiency without excessive waveform distortion.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple consumers are operated in parallel with phase control, then power distribution flexibility is improved, but harmonic repercussions on the network increase

Engineering Contradiction:
Improvepower distribution flexibilityVSAvoidnetwork harmonics
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the control of multiple consumers into different half-wave assignments, where Consumer 1 is controlled on positive half-waves and Consumer 2 on negative half-waves. This segmentation prevents simultaneous phase-controlled switching of multiple consumers, thereby reducing cumulative harmonic generation while maintaining flexible power distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces asymmetric control patterns where different consumers are assigned to different polarity half-waves. This asymmetric assignment creates opposing harmonic signatures that cancel each other out, reducing net harmonic repercussions on the network while preserving system versatility.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2732542B1Method of operating several loads fed from an ac grid by means of phase controlled converters
Publication Date: 2018.03.07 SINGULUS TECHNOLGIES AG
  • EP2732542B1 patent drawingFigure 1
  • EP2732542B1 patent drawingFigure 2(a)~2(c)
  • EP2732542B1 patent drawingFigure 3(a)~3(c)

AI summary

The invention relates to a method for operating a first and a second electrical load in an alternating current network. The method can be operated in an optional first operating mode, in which the positive and negative half waves for each load are controlled with a first phase angle. In addition, a second operating mode is provided, in which a first part of the positive and negative half waves for the first load and a second part of the positive and negative half waves for the second load are controlled with respective second phase angles. The invention further relates to a device for performing the method, having first and second phase angle control for the first and second loads.